I'm going to give a part of the answer myself from something I found on the internet:

As an example, consider the plant species Taxus brevifolia. This species produces a compound, taxol, which is useful for treating cancer. Unfortunately, large quantities of bark from this rare tree are required to produce enough taxol for a single patient. Through cladistic analysis, a phylogeny for the genus Taxus has been produced that shows Taxus cuspidata, a common ornamental shrub, to be a very close relative of T. brevifolia. Taxus cuspidata, then, may also produce large enough quantities of taxol to be useful. Having a classification based on evolutionary descent will allow scientists to select the species most likely to produce taxol.

seems like an interesting and rather specific course, but I can speculate that the phylogeny of insect pollinators is important because understanding their evolution and ancestral species could give insight into the origin of relations that the pollinators share with plants. Some insects and flowers have co-evolved in very specific fashions, and these instances are very interesting to some, while providing a nice template for evolution. By looking at the insect phylogeny, it may give insight to when the relationship developed, because many of the adaptations for co-evolution are phenotypic changes. Hope that helps!

It also seems important in a process called "pathogen spillover" (The transmission of infectious agents from a reservoir population (for example commercial bumble bees) to a sympatric wild population). This happens when commercially bred bumble bees are transported to other countries to aid in the increasing demand for pollination

=> Pathogen spillover seems most likely to occur when the reservoir host and potential novel host are phylogenetically close (e.g., Perlman & Jaenike 2003). So in this case phylogenetics might aid to assess where certain bumble bee species can be introduced (in regions where the wild bumble species is a rather distant relative) and where not (In regions where the wild bumble bee species are rather close relatives)?

So I'm guessing that in the case of the insect-plant co-evolution the same principle can be applied? That when a certain bumble bee population declines/goes extinct (what is actually happening at the moment in a lot of countries), phylogenetics can give clues as to which bumble bee species/subspecies can be introduced to re-establish the pollinator-plant interaction in a certain region. Although this reminds me of my applied ecology course, that introducing replacement species to restore function can have drastic results on the community/ecosystem

Phylogeny also is needed to understand when you're looking at divergent (new species in same clades evolving in parallel) or convergent (new pollinator / plant relationships built on shift in old abilities) evolutionary patterns.